Photometric sky surveys performed in different regions of the electromagnetic spectrum are designed to include shallow or deep magnitudes, according to the purpose of the researchers. However, transformations between different photometric systems can be used as a tool to combine shallow and deep magnitudes. These transformation equations can also be produced in terms of luminosity and metallicity. In the literature, transformation equations are given for main-sequence stars [1]}, [2]}, [3]}, [4]}, [5]}, [6]}, [7]}, [8]}, [9]} and evolved stars [10]}, [11]}, [12]}, [13]}, [14]}. Transformation equations between the photometric systems have been obtained for approximately 20 years and used effectively to investigate the structure and evolution of our Galaxy. UBV is one of the important photometric system in the optical region [15]} which is used to determine the photometric metallicities of the stars and the interstellar absorption. The \(U-B\)  colour index plays an important role in these determinations, while its combination with the colour index \(B-V\)  can be used in determination of the reddening of stars. In the UBV photometric system, the colour excess \(E(B-V)\)  of a star can be determined by the \(Q\)  method or by shifting its observed \(B-V\)  colour index along the reddening vector in the \(U-B\times B-V\)  two-colour diagram up to the intrinsic colour index \((B-V)_0\)  [15]}. While the colour excess \(E(U-B)\)  can be calculated by the equation of the reddening line, i.e. \(E(U-B)=0.72\times E(B-V)+0.05\times E(B-V)^2\) . [17]} discovered that stars with weak metal lines have larger ultraviolet (UV) excesses than the ones with strong metal lines. [18]}, [19]}, and [20]} confirmed the work of [17]}. Thus, metal-rich and metal-poor stars could be classified not only spectroscopically, but also photometrically, i.e. by their UV excesses. [22]} noticed in a \((U-B)_0\times (B-V)_0\)  two-colour diagram of a set of stars in solar neighbourhood that stars with the same metallicity have a maximum UV excess at the colour index \((B-V)_0=0.6\)  mag, and introduced a procedure to reduce the UV excesses of the stars to the one of colour index \((B-V)_0=0.6\)  mag. The relation between the UV excess and metallicities of stars have been used by the researchers for their metallicity estimation via photometry i.e. [23]}, [24]}, [25]}, [26]}, [27]}, [28]}, [29]}, [30]}. Similar calibrations have been developed for the SDSS photometric system and applied to faint stars [2]}, [3]}, [33]}. These calibrations were used to calculate metal abundances [34]}, [35]}, [36]} and estimation of the Galactic model parameters for different populations [37]}, [34]}, [39]}, [40]}, [41]}.
